1. Field of the Invention
Embodiments of the invention generally relate to methods and apparatus for determining individual phase fractions and/or flow rates of multiple phases within a fluid flow.
2. Description of the Related Art
In the petroleum industry, as in many other industries, ability to monitor flow of certain fluids in process pipes in real time offers considerable value. Oil and/or gas well operators periodically measure water/oil/gas phase fraction flow rates within an overall production flow stream containing a mixture of these three phases. This information aids in improving well production, allocating royalties, properly inhibiting corrosion based on the amount of water and generally determining the well's performance.
While some techniques enable measuring flow rates within two phase mixtures, difficulty arises in determining individual volumetric fractions and flow rates in three phase mixtures. Separators can be used to separate out one or more phases from the flow stream but introduce additional equipment, time and costs. Other costly and time consuming procedures entail manual sampling of the mixture to obtain information regarding the individual volumetric fractions. On the other hand, flowmetering devices can be complex and can restrict flow creating significant pressure loss, such as when venturi based measurements are required.
Therefore, there exists a need for improved methods and apparatus that enable determining individual phase fractions and hence flow rates of multiple phases within a fluid flow.